Elevation filters seed traits and germination strategies in the eastern Tibetan Plateau

Abstract

Seeds are the colonizing propagules for many plants and may therefore contribute to the filtering of species during the process of colonization and community assembly. Environmental filtering of seed traits may occur among species and influence community composition, or within species and influence the environmental breadth that a given species inhabits. To test for evidence of such filtering of seed traits, we measured morphological and germination traits of seeds of 408 angiosperm species collected across an elevational gradient in the eastern Tibetan Plateau grasslands. We tested for elevational filtering of traits at the species level, as well as within 22 of those species that occurred at different elevations, in order to test whether within‐species variation reflected among‐species patterns. Elevational patterning occurred in both seed morphology and seed germination. Seeds were smaller, more elongated and had a higher surface area:volume ratio and shorter germination times at higher elevation. Seed morphology was associated with germination such that more elongated and smaller seeds with a higher surface area:volume ratio germinated faster, leading to earlier germination in seeds from high elevation. Within species, elevational variation in seed traits was observed in several species, but species differed in how those traits were distributed across elevation. These results suggest that taxonomic differences in seed traits may contribute to elevational variation in the species composition of plant communities, but that seed traits may be variably selected by elevation within species.

Transgenerational Genetic Effects Help Explain Latitudinal Variation in Seed Mass and Germination Timing in Plantago lanceolata

“…Multiple biologists have argued that we must begin to examine how populations within species vary genetically across geographic and environmental gradients [24,60,63]. This requires taking advantage of experimental designs that focus specifically on characterizing the genetic control of seed traits.…”

“…In others, mass increases poleward [33,40,[42][43][44][45][46][47][48][49], and with increasing altitude [30,[50][51][52][53] or shows no geographic trend [32,33,[54][55][56][57][58][59]. Geographic patterns in temperature requirements for germination and germination rate are equally diverse [36,51,53,[60][61][62][63][64][65].…”

How do distinct facets of tree diversity and community assembly respond to environmental variables in the subtropical Atlantic Forest?

“…However, our study revealed a recent pattern of adaptation toward lighter seed mass in highland forests, independent of phylogenetic information (Figure 2e), indicating convergence in SM values toward higher altitude conditions. Past evolution and phylogenetic history determine seed mass (Wang et al, 2021), which affects the ability of lineages to colonize sites or persist under different environmental conditions.…”

Geographical patterns and environmental influencing factors of variations in Asterothamnus centraliasiaticus seed traits on Qinghai-Tibetan plateau

“…Seeds are believed to be smaller and more elongated, with a larger surface area at higher altitudes ( Bu et al., 2007 ; Qi et al., 2014 ). Some studies believe that this greater surface area is conducive to faster germination, highlighting the direct influence of seed morphology on germination ( Ruprecht et al., 2015 ; Wang et al., 2021 ). However, the veracity of these claims is still under debate.…”